High frame rate and high resolution video cameras use high data rates to effect proper operation. In order to minimize channel bandwidth and data rate, it has been proposed to use a multichannel sensor array, such as disclosed in U.S. Pat. No. 4,322,752, issued Mar. 30, 1982, inventor Bixby. Typically, each channel is provided with amplifier and other signal processing circuitry. Where the image from the sensor is to be stored in digital memory, each video channel is provided with an analog-to-digital converter. One of the difficulties to be dealt with in using a multichannel sensor is the requirement that the transfer characteristic, relating output signal amplitude to sensor illumination, be uniform across all channels. Even minor nonuniformities can be readily detected as banding by the human eye, when the image is displayed on a video display. Thus, each video channel must be adjustable to calibrate it for optimum signal characteristics. It is advantageous that the control for such adjustments be efficient, cost effective and noncomplex.
Serial data and control communication, as opposed to parallel data and control communication, can effect such advantageous communication. However, known serial communication techniques as disclosed in the following patents, do not address the problems of a multichannel image sensor imaging system.
U.S. Pat. No. 4,918,589, issued Apr. 17, 1990, discloses a method and apparatus for linking processing in a hierarchical control system. The disclosed system is highly complex, expensive, and not readily adaptable to the requirements of a multichannel imaging system.
U.S. Pat. No. 4,959,773, issued Sep. 25, 1990, inventor Landers, discloses an adapter for attaching I/O devices to I/O communications with alternating read and write modes link. Only a single channel is linked between an MPU RAM and a Display RAM. Multi channel links are not used.
U.S. Pat. No. 4,999,768, issued Mar. 12, 1991, inventor Hirokawa, discloses data transfer control units each of which comprises processors and dual-port memory. There is no disclosure of a serial link between the signal channels of a multichannel imaging system.
U.S. Pat. No. 4,514,823, issued Apr. 30, 1985, inventors Mendelson et al., discloses apparatus and method for extending a parallel channel to a serial device. There is no disclosure in this patent of a serial link between the signal channels of a multichannel imaging system.
There is thus a problem in imaging systems having multichannel image signal readout, to provide a communication link to control the multiple channels. Such a link should be simple to implement, allow for easy and unlimited expansion, allow other actions at an input station other than exchanging data to and from the station, and eliminate the need for a processor at the receiving station.